Salt Marsh Foraminifera, St. Catherines Island, Georgia: Ecology, Taphonomy, Paleoecology

北美东北部的盐沼和沼泽有孔虫组合与墨西哥湾的有孔虫组合明显不同，但它们之间关键的动物群转换——尤其是美国东南部海岸的沼泽组合特征——基本上没有被研究过。同样，这些沉积物中有孔虫试验的损失、保存或重新分配的短期和长期方面仍然很大程度上是未知的。本文提出的工作旨在解决两个问题：东南盐沼有孔虫的生态学和地学意义。乔治亚州圣凯瑟琳岛（St. catherine Island）的现代和残余（-200年至1500年以上）盐沼沉积物为盐沼有孔虫的地学和古生态学研究提供了理想的环境。现代沼泽分布广泛，提供了现代环境的例子，可以与更古老的残余沉积物的“古环境”进行比较。沿着岛屿东部边缘广泛暴露的废弃盐沼沉积物包含了保存完好的关键原址特征，这些特征使人们能够识别出在现代沼泽中描述的特定盐沼栖息地和亚环境。这些沉积物中有孔虫和其他微化石丰富。因此，对这些残余沉积物的有孔虫的分布研究基本上可以利用与研究现代沼泽相同的方法来实现。本研究的目的是记录和比较有孔虫在圣凯瑟琳岛现代和遗留沼泽沉积物中的分布模式。研究结果将涉及生物地理学、生态学、古生态学、古环境解释，特别是地貌学和地貌学的评价。

Salt marshes and marsh foraminiferal assemblages of northeastern North America differ appreciably from those of the Gulf of Mexico, yet the crucial faunal transitions between them-- especially marsh assemblages characteristic of the southeastern U.S. coast--remain essentially unstudied. Similarly, short- and long-term aspects of loss, preservation, or redistribution of foraminiferal tests in these sediments remains largely unknown. The work proposed herein is designed to address both problems: the ecologic and taphonomic significance of southeastern salt marsh foraminifera. Modern and relict (-200 to 1500+ year old) salt marsh sediments of St. Catherines Island, Georgia, provide and ideal setting for studies on the taphonomy and paleoecology of salt marsh foraminifera. Modern marshes are extensive and provide examples of modern environments for comparisons with the "paleoenvironments" of the older relict deposits. Relict salt marsh sediments, extensively exposed along the eastern margin of the island, contain key, well-preserved, in situ features that permit the identification of those specific salt marsh habitats and subenvironments that have been described in modern marshes. Foraminifera and other microfossils are abundant in these deposits. A distributional study on foraminifera of these relict deposits therefore can be achieved utilizing essentially the same methods applicable to studies on modern marshes. The purpose of this study is to document and compare distributional patterns of foraminifera in modern and relict marsh sediments of St. Catherines. Results will address problems of biogeography, ecology, paleoecology, paleoenvironmental interpretations, and particularly the assessment of taphonomy and taphofacies.